Table 1.
Main causes of fluctuation, and whether levels increase (↑), decrease (↓) or are unaffected (=), in the circulating levels of vertebrate blood cells (from Stockham & Scott 2002 and Feldman et al. 2000)
| Cell type | Sustained stress (glucocorticoids) |
Alarm response (epinephrine) |
Acute bacterial infections |
Chronic bacterial and protozoan infections |
Viruses and proteo-bacteria |
|---|---|---|---|---|---|
| Lymphocytes | ⇊ | ⇈ | ↓ | ↑ | ↓ = ↑1 |
| Neutrophils | ⇈ | ⇈ | ⇈ ↓ 2 | ↑ | ↓ = ↑1 |
| Monocytes | ↓ ↑ 3 | = | ↑ | ⇈ | = |
| Red blood cells* | = | ↑ 3 | ↓ | ↓ | ↓ |
⇈: Usually. ↑: In some cases.
1
Depending on the pathogen.
2
Overwhelming inflammation is often associated with a decrease of neutrophil levels, accompanied by evident clinical manifestations.
3
Depending on the host species.
*
Besides the effects of deficient nourishment and metazoan parasites.